Manufacture of 1, 2, 2-trichloro-1, 1, 2-trifluoroethane



United States 2,8,543 Patented Sept. 2, 1958 MANUFACTURE OF l,2,2-TRECHLORO-1,1,2-

V 'E'RIFLUOROETHANE Cyril Woolf, Long island City, N. Y., assignor to Allied Chemical Corporation, a corporation of New Jerk No Drawing. Application February 17, 1954 Serial No. 411,017

8 Claims. (Cl. 26l)-653) This invention relates to manufacture of 1,2,2-trichloro-l,1,2-trifluoroethane, CCl FCClF If obtainable in a condition not too contaminated with other chlorofluorocarbons, CCl FCClF (B. P. 47.7 C.) is a particularly desirable and valuable material for use as a primary source of chlorotrifluoroethylene which in turn is employed as a monomer in certain polymerization processes. As far as now known, some prior methods for making CCl FCClF are such as to result in production of mixtures of CCl FCClF and CCl CF along with mixtures of CCl FCF and CClF CClF While the tetrafluorinated compounds may be fairly easily separated from the trifluorinated compounds, the mixture of trifiuorinated materials contains a relatively large proportion of CCl CF (B. P. 45.9 C.), and because of the very close boiling points of the trifluorinated compounds,

reasonably good separation of the trifluorinated isomers is at best commercially unattractive. Other known operations for making CCl FCClF involve production of mixtures comprising dominantly CCI FCClF and CClF CClF and usually include appreciable amounts of the respective CCl CF and CCl FCF isomers. On the one hand, the presence of unacceptably large amounts of CCl CF present the difiiculty of its separation, and on the other, particularly with regard to manufacture of CCl FCClF as major product, the formation of substantial amounts of the tetrafluorinated compounds represents waste of organic starting material and fluorine.

The major object of the present invention lies in the provision of processes for making CCl FCClF from CCl =CCl which is a relatively low cost and readily available organic starting material, by easily controllable gas-phase catalytic operations which function in such a way as to efiect production of CCI FCCIF without the formation of any objectionable quantities of unwanted chlorofluoro carbons which are inherently and disadvantageously formed in the prior art methods.

In accordance with the invention, it has been found that certain herein disclosed zirconium tetrafluorides (ZrF have the property, under certain operating conditions, of catalyzing the reaction of C Cl free chlorine and hydrogen fluoride in such a way as to effect formation of good yields of CCl FCClFg reaction product containing substantially no tetrafluorinated chlorofiuorocarbons and having such a low CCI CF isomer content as to be economically unobjectionable when the major CCl FCClF product is to be utilized as a process chemical, for example, as charge to a dechlorination step to produce chlorotrifluoroethylene.

Zirconium fluorides including the anhydrous ZrF are known in the art. However, zirconium fluorides in general, though possibly of powdery and small discrete particle characteristics, are composed of ZrF crystals of relatively large size, i. e. not less than one thousand and usually several thousand Angstrom units radius and above. Other forms of ZrFs as described herein, when examined by the highest powered optical microscope, appear to be of non-crystalline or amorphous structure. When these amorphous, by ordinary standards, zirconium fluorides are examined using X-ray diffraction technique, such materials are found to be bordering on the amorphous condition, and are extremely small, submicroscopic crystals which are designated in the art as crystallite. According to the invention, the ZrF catalysts thereof are catalytically usable size (mesh) increments, e. g. granules or pellets, which are constituted of such amorphous zirconium fluoride having crystallite size. The desired catalytic activity prevails in zirconium fluorides of crystallite size of about 400 Augstrom units radius or below. As crystallite size decreases below this value, desired catalytic activity increases and particularly preferred zirconium fluorides include those having crystallite size of about A. and below, as determined by X-ray diifraction technique.

The scope of the invention includes substantially anhydrous zirconium fluorides (ZrF having the indicated crystallite size, and provided such fluorides are derived by reaction of substantially anhydrous ZrCl and substantially anhydrous hydrogen fluoride. The improved catalytic material employed is prepared by treating Zrcl which is preferably as anhydrous as commercially feasible and preferably in pure form but may suitably be of commercial or technical grade, with preferably excess quantities of inorganic fluorinating agent reactive therewith under conditions such that no liquid water is present in the reacting materials. For example, catalyst may be prepared by treating solid substantially anhydrous zirconium chloride (intended herein to designate ZrCL; and not other forms of zirconium chloride) with gaseous substantially anhydrous HF. In a gas phase fluorination operation, using HF, temperatures may be anything from above the vaporization point of HF up to about 250 C. at which temperature e. g. anhydrous ZrCL; begins to sublime appreciably. If desired, the reaction may be carried out with fluorinating agent in the liquid phase. In the catalyst synthesis reaction, HF displaces HCl causing transformation of ZrCl to ZrF To condition the material for better catalytic use, the resulting zirconium fluoride may be heated in an anhydrous atmosphere at elevated temperature, i. e., temperature at which conditioning or activation takes place. The finished catalyst is then recovered. Heating the ZrF in a stream of dry nitrogen or anhydrous HF gas for about one to four hours at temperatures of about 300-350 C. or four to six hours at 250-300 C. is ordinarily suitable for this purpose. In some circumstances, the catalyst may be activated by heating the ZrF in a stream of free oxygen-containing gas such as oxygen or air at about 400-500 C. for approximately 30 minutes to eight and one-half hours, depending mostly on the oxygen content of the treatment gas, in which case conditioning with dry nitrogen or HF gas as above mentioned may be omitted.

Zirconium fluorides prepared by the above described method of treating anhydrous ZrCl with substantially anhydrous HF have been found to be composed of crystallites of size below about 400 A., and generally substantially below 150 A. as is desired for use in the invention. Gas-phase preparation of catalyst is illustrated in the following example, in which parts and percentages, unless otherwise noted, are on a weight basis.

Example A 180 parts of 4 to 14 mesh anhydrous zirconium tetrachloride of commercial grade were charged to a one inch I. D. tubular nickel reactor provided with inlet and outlet connections for a gas stream and means for externally cooling the reactor by blasts of air. An externally disposed electrical resistance heater was also supplied to furnish heat to the reactor when needed.

Gaseous anhydrous HF, initially at the rate of 20 parts bed'of solid zirconium chloride.

a :3) per hour, was passed through the reactor while maintaining the maximum internal temperature in the reactor in the range of 6070 C. by adjusting the extentof external cooling. Reaction of ZrCl and HF to form ZrF and HCLwaseflected. Means were provided for sampling'the reactor efliuentgas to determine the presence of HF and/ or HCI. Initially, the'point of maximum reaction temperature was near the upstream end of the Exit gas from the reactor was periodically sampled and when the evolution of HCl began tojslacken and HF began to appear, the reaction temperature was gradually raised to 200 C. After 5 hours reaction, the reactor effluent gas contained only HF and .was substantially free of HCl; 130 parts of zirconium fluoride, containing 98% ZrF 'and less than 0.5% chlorine, in hard granular form and having substantially. the same mesh .size .as the initial zirconium chloride, were'obtained. 1 An X-ray diflraction pattern of zirconium fluoride catalyst so prepared showed that the material, constituting the approximate 4 -14 mesh catalyst, had average crystallite size ofabout 50 Angstrom units radius, i. e. the 'crystallite size was so small as to be indicative of amorphous structure.

If, in a gas-phase operation such as just detailed, the ZrCl is initially in very fine or powdery form, prior to HP gassingthe material may be pelleted to e. g. 425 mesh size, in' which case pelleting should be done preferably under conditions as anhydrous as feasible.

Another suitable and convenient'means for preparing the zirconium fluoride catalyst is to add solid anhydrous ZrCl to anexcess of liquefied anhydroushydrofiuoric acid in a cooled container and, after complete addition of the ZrCl mildly agitate the mixture until reaction is substantially complete. The ZrF so prepared maybe then conditioned or activated as outlined above. Following is an examplein which parts and percentages are on a Example B 175 parts of granular" (4 to 14 mesh) anhyrous ZrCl; ofcommercial grade were added in small portions to liquid anhydrous hydrofluoric acid contained in an externally cooled. vessel.- Vigorous exothermic reaction took place and additional amounts of liquid anhydrous HF were added as needed to maintain an excess thereof. After allthe zirconium chloride had been added, the mixture was stirred to promote residual reaction. When reaction of zirconium chloride appeared complete, the mass was mixed and stirred with additional liquid hydrofluoric acid and excess HF- was removed by slowly boiling the mixture. 125 parts of anhydrous zirconium fluoride of about 4-20 mesh size having greater than 98% ZrF content and containing less than 0.5% chlorine were recovered. This ZrF was heated in a stream of dry inert gas (nitrogen) at a sufficiently elevated temperature, about .300 C., and a period of time sufficiently long, about 3 hours, to condition and activate the material. The mesh size distribution of the ZrF particles did not change substantially during the latter heat treatment. An X-ray dilfraction pattern of the catalyst thus prepared showed that the 420 mesh catalyst comprises material between 60% ill of average crystallite size of about 50 -A., i. e. the crystal- 7 lite size was so structure. 7

While the mechanisms of intermediate reactions taking place in practice of the invention are not entirely clear, when using CCl =CCl elemental chlorine and anhydrous HF as raw materials, the net; resultfunder the operating conditions specified, appears to be 7 small as to be indicative of amorphous noncrystalline 0012 0012 3HF C1: Z? CClzFC 01F: 3N0] Reaction zone temperatures are maintained at or above the level at which fluorination of the CCl ==CCl organic 4 starting material begins to take place in the presence of gaseous HF and free chlorine. Reaction takes hold at temperature as low as about 225 C., but commercially significant reaction appears to require temperature of about 240 C. and above. Temperature should not exceed about 400 C. since it has been found that higher temperatures promote increase in the reaction products of undesirable amounts of the unwanted CCl CF At maximum temperatures of about 400 C., the CCI CF content of recovered CCl FCClF maybe held below about 10% by Weightand generally in most operations not more than about 7% by Weight. At maximum temperature of about 375 C., the CCI CF content may be kept not more than about 5% by weight of the CCl FCClF recovered, comparison of appended Examples 1 and 2 indicating higher CCI CF content and somewhat lower eral, the quantities of HF and Cl utilized are sufficient to provide for formation of chlorofluorocarbon reaction product containinga worthwhile quantity of CCl FCClF Preferably, amounts of HF andCl should not exceed theoretical requirements;and depending upon particular operating conditions, quantities of HF; may vary from 2 to 3 mols per mol of C Cl and to facilitate good utilization of chlorine amounts of the latter are preferably and o-f thcory penxpass of .C C l, thru the reactor.

Time of contact of C Cl starting material with zirconium fluoride catalyst may be varied substantially without noticeable sacrifice of efiiciency, of operation. However; if contactv time is excessive "i. e'. .low space velocities," the capacity of g the reactor --is lowthereby causing economic disadvantages in' the operation. On

the other hand, if contact timeistoo short, there'actionof starting. material to form desired product may be incomplete thereby entailing possible high cost of recovering and recycling unreactedmaterial tosubsequent operation. In any event, contact time shouldbe sufficient to effect fluorinating reaction ;of a commercially notable amount of the C CL; starting material. Contact time may lie in the range of aboutone 'to ,25'seconds,- preferably about 2 to 8- seconds. In a particularoperati'on, optimum contact time, within thevalues indicated is*dependent upon variablessuch as scale of operation, quantity of catalyst in the reactor, and specific apparatus employed and may be best determined by a test run. "Atmospheric pressure operation is preferred, but'the reaction may, if desired, be carried out at superatm'o'spheric or subatmospheric pressure, the choice of pressure being largely one of convenience. V I V Any suitable chamber or reactor tube constructed of inert material maybe employed for carrying out the reaction provided the reaction zone afforded is of suiiicient length and cross-sectional 'area to accommodate an adequate amount of catalyst and afford sufficient space for passage of the gas mixture at an economical rate of flow. Material such as nickel, graphite, Inconelor other materials resistant to HP are suitable for use as reactor tube. Externally disposed conventional means may be employed to maintain the desired catalyst bed temperatures.

Reaction products may be recovered by conventional procedure. The temperature of the gas streamiexiting the reactor may be lowered inan initial cooler to e. g. 20 to 60 C., the gas stream then scrubbed with water to condense high boiling chlorofluorocarbons and remove HF and HCl from the gas stream, passed thru aqueous caustic solution to remove chlorine and res idual' small amounts of HCl and HF, then passed over calcium chloride or other drying agent, The gas stream is then run thru a cold trap maintained at temperatures substantially below the boiling point of the lowest boiling material present, e. g. by indirect cooling of the gas in a bath of acetone and carbon dioxide ice. High boiling chloro fluorocarbons condensed in the water scrub solution are separated therefrom, and these organic condensates together with those from the initial gas cooler are combined with the condensate of the cold trap. The resulting composite liquor comprising reaction products and unreacted starting material, is fractionally distilled to separate components to the extent desired.

In accordance with another feature of the invention, the reaction is carried out in the presence of extraneously introduced C CL F either CCI FCCI F (B. P. 92.8 C. or CCl CClF (B. P. 91 C.). The invention reaction involves production of sought-for major product CCl FCClF a minimum amount of the unwanted CCI CF isomer, and, as shown for instance in appended Examples 1 and 2, a substantial amount of CCI CCIF and smaller amounts of CCl CCl F (B. P. 138 C.) are also formed. Herein the expression extraneously introduced C CL F is intended to mean C Cl F introduced as such at the as inlet end of the reactor and distinct from the primary raw materials C Cl elemental chlorine and HF. That is, extraneously introduced C Cl F desi nates the superimposition of this material on reactants in a reaction zone as a material separate and distinct from the CCl CClF inherently formed during one pass of the major reactants through the reaction zone. Hence, in operation of a preferred embodiment of the invention, during a pass thru the reactor, the latter contains some CCl CClF inherently formed by the reaction of the incoming C Cl elemental chlorine and HF, plus some extraneously introduced CCl CClF purposefully charged into a reactor along with the incoming raw materials. While the extraneously added C Cl F may 'be CCl FCCl F, as a matter of practical consideration CCl CClF is preferably employed and is utilized herein by way of exemplification.

In accordance with the instant feature of the invention, it has been found that the imposition of extraneously introduced CCI CCIF on the reaction serves, in some way or other, to efiect an overall operation the net result of which is a CCl FCClF product having a substantially reduced unwanted CCl CF isomer content as compared with operations carried out in the absence of the superimposed CCl CClF This reduction of CC1 CF content of the major product is exemplified by comparison for instance of appended Examples 3 and 4 on the one hand and Example 5 on the other. The mechanisms involved in the lowering of the CCI CF content by the presence of extraneously introduced CCl CClF are not wholly understood. Net reaction involving production of the trifluorinated compound CCI FCCIF product is substantially exothermic. Practice indicates that, probably because of the exothermic characteristics of the main reaction i. e. production of CCI FCCIF from the incoming C Cl chlorine and HF, there is a marked tendency to create hot spots along the various points in the reactor when the reaction is carried out in the absence of extraneously introduced CCl CClF On the other hand, fiuorination of CCl CCiF (whether inherently formed or extraneously introduced) to CCI FCCIF is endothermic. Hence, since experience shows that unduly high temperatures promote CCI CF formation, the possibility exists that because of the endothermic fiuorination of CCl CClF to CCl FCClF the extraneously introduced CCl CClF may serve to smooth out temperatures in the reactor, prevent the presence of hot spots and thereby reduce the amount of unwanted CCl CF isomer formed during a single pass thru the reactor. HoWeVer, regardless of theories, practice demonstrates that the presence in the reactor of extraneously introduced CCl CClF significantly cuts down the unwanted CCI CF content 6 of the sought-for cCl FCClF product. Superimposi-' tion on the reaction of the CCl CClF affords the further highly economic advantage of increasing overall This additional CCl FCC1F production of the process. advantage appears to arise from the probability that extraneously introduced CCl CClF suppresses formation of inherently produced CCl CClF and from the fact that the extraneously introduced CCl CClF if it reacts at all during a pass thru the reactor, is itself converted to the sought-for CCl FCClF product.

ln accordance with the invention it has been found that the foregoing advantages with regard to minimization of formation of CCl CF become noticeable with the presence in the reactor of any appreciable amount of extraneously introduced C Cl F However, it is desirable to conduct the reaction in the presence of extraneously introduced C CL F in the amount in the approximate range of 0.l1.0 mol proportions based on the amount of C Cl fed, and, to facilitate high production of CCI FCCIF preferably in the approximate range of 0.8-1.0 mol proportions as illustrated for instance by Examples 6 and 7. When reaction zone temperature is maintained not more than about 375 C. and reaction is carried out in the presence of extraneously introduced C Cl F preferably CCl CClF in amount of at least 0.1 mol proportion and generally in the approximate range of O.1l.0 mol proportions based on the amount of C Cl fed, the CCl CF content of recovered CCl FCCIF may be held below and generally substantially below 5% by weight. The extraneously introduced C Cl F as used in the operation may be material obtained entirely from outside the process or may be CCl CClP recovered from the distillation step already described and recycled through the reactor.

It has also been found that in certain commercial operations it is advantageous to pass the incoming vapor phase CCl =CCl initially thru a bed of activated carbon maintained at elevated temperature prior to mixing the thus treated C Cl with the elemental chlorine and anhydrous HF, and with the extraneously introduced CCI CCIF if employed. The activated carbon may be maintained at temperature in the range of 250-400 C., and, as above described, temperature range of the zirconium fluoride catalyst may be anywhere u'thin the 225-400" C. range indicated. If the activated carbon treatment is employed, only the C Cl should be passed thru the activated carbon, it having been found that, by doing, most importantly overall formation of the mono fluorinated CCl CCl F is minimized. Further, it has been observed that reaction of C C1 and chlorine should be carried out in the main ZrF reactor in the presence of the HF, since it appears that by effecting, in the presence of HF, whatever reaction which does take place between C CL; and chlorine, the fiuorination operation as a whole is substantially activate-d, probably caused 'by the presence of HP at the instant of chlorination of the C 01 Major advantages of use of the activated carbon lie in two features, namely, substantial increase of longevity of the ZrF catalyst, and also the possibility of operating the ZrF catalyst in the lower portion of the indicated 225400 C. temperature range. Thus, when incoming C Cl is initially passed thru activated carbon,

it becomes possible and it is preferred to maintain temperature in the fiuorination reaction zone in the approximate range of 240300 C. Further, it has been found that when operating the main ZrF reactor in conjunction with treatment of incoming C CL; by activated carbon, in most instances, chlorine utilization is improved where the ZrF catalyst prior to any use as such is subjected to the oxidation treatment hereinbefore described.

Example ].200 cc. of about 414 mesh zirconium fluoride catalyst (ZrF prepared by procedure substantially the same as illustrated in Example A above and having crystallite size less than about A., were charged into a nickel reactor tube. The tube was ext ternall'y electrically heated and theitube ends were fitted with p1pe connections for the inlet and outlet of agas stream and for the insertion into the nickel'tube and catalyst bed "of 'a suitable thermocouple. Liquid CCl =CCl2 was vaporized and mixed with gaseous anhydrous HFand free chlorine in the proportion of 1.9 mols of HF, 0.75 molCCl =CCl and 0.95 mol of C1 and the mixture introduced at the rate corresponding with 0.75 mol of CClFCCl per hour into the inlet'end 'of the nickel tube and passed through the bed of ZrF ber to remove chlorine, a dryer containing CaCl as the drying agent, and a condenser held at about minus 78: C. (to separate small quantities of extremely lowbolling by-products) by means of an external cooling bath of'carbon dioxide ice and acetone. 'After about 4 hours,- operation was discontinued. Condensates from the initial cooler, the water scrubber and the low temperature condenser were combined and distilled. Of products formed, there were recovered 12 mol percent CCl CCl F (B. P. 138 C.), 42 mol percentCCl CClF (B. P. 91 and 46 mol-percent of ccl rcclr (B. P. 47.7 C.) containing about by weight of CCl CF (B. P. 45.9 C.). About 287 grams of CCl FCClF were recovered per hour per liter of catalyst. Utilization of raw materials was 91% of the HF, 91% of, the C 01,, and 72% of the chlorine.

Example, 2.-ln this example, the same catalyst and apparatus were employed as in Example 1. Liquid CC1 CCl was vaporized and mixed with gaseous anhydrous HF and free chlorine in the proportion of 1.8

. mols of HF,- 0.78 mol CCl =CCl and 0.95 mol of C1 and the mixture introduced at the rate corresponding with 0.78'mol of CCl =CCl per hour into the inlet end of the nickel tube and passed through the bed of ZrF catalyst. Contact time was about 4 seconds. Temperature of the catalyst bed was maintained throughout the run close to and at a maximum of about 385". C. The gaseous products of the reaction were handled as in Example 1, and after about 2 /2 hours, operation was discontinued. Condensates from the initial cooler, the water scrubber and the low'temperaturecondenser were combined and distilled. Of products formed, there were @recovered 16 mol percent CCI CCI F, 38 mol percent CCl CClF and 46 mol percent of CCl FCClF containiug about 7% by weight of CCl CF About 280 grams of CCI FCCIF were recovered per hour perliter of catalyst. Utilization of raw materials was 85% of the HF, 83% of the C Cl and 68% of the chlorine.

Example 3.In this example, the same. catalyst and apparatus as in Example 1 -.were employed. Liquid CCl =CCl was vaporized and mixed with gaseous anhydrous HF and free chlorine in the proportion of 1.75 mols of HF, 0.75 mol cc1 cc1 and 0.90 mol of C1 and the mixture introduced at the rate corresponding with 0.75 mol of CCl =CCl per hour into the inlet'end of the nickel tube and passed through the bed of ZrF catalyst. Contact time was about 4 seconds. Temperature of the catalyst bed was .maintained throughout the run close to and at a maximum of about 352 C. The gaseous products of the reaction were handled as in Example 1, and after about 4 and one quarter hours, operation was discontinued. Condensates were combined and'distilled; Of products formed,'there were recovered mol percent'CCl CCl F, 43 mol percent CC1 CClF and 42 mol percent of CCl FCClF 'containing about 5 by weight of CCl CF About .235 grams of CClgFCClF:

were recovered;per;:hourper liten of catalyst. Utilization of raw materialswas,90% of the 84% of the C Cl ,-and:70%"of thechlorine1 f Example 4.-1l0 ccifof about'4-14'mesh zirconium fluoride catalyst, prepared'byprocedure substantially. the

same as illustrated .in Example'A above-and having crystallite size .less than about 150 A.,-v were'charged into the reactor.- Apparatus employed, was substantially the same as'in Example 1.' Liquid CCI CCI waS vaporized: and mixed with. gaseous anhydrous andfree chlorine in the proportion of 1.25 mols" of HF,- 0.58 mol CCl =CCl and 0.60 mol of Cl ,-and the mixture introduced. at the rate corresponding with,0.58" mol of CClg -CCI per hourintothe inlet endof the nickel tube and passed 'throughthe bed' of'ZrF catalyst,"'Contact time was about 6 seconds. Temperature of the catalyst bed was maintained throughout the run close toa'ndat a maximum of about 362 C. Gaseous products were handled as in Example 1, and after about 4. and. one third hours, operation 'was'discontinuedp Condensates werecombined and distilled. Qfproducts formed, there were recovered 14 mol percent CCl CCl- F, 38 mol percent CCl CClF and .48 mol percent of CCl FCClF containing about 5% by weight of CCI CF About 300, grams of CCI FCCIF were recovered per hour per liter of catalyst. Utilization of raw materials was of the HF, 74% of the C Cl and 71% of the chlorine.-

Example 5.The same catalyst and apparatus as in Example 4 were employed.- Liquid CCIZTI-CCIZ was vaporized and mixed with gaseous anhydrous HF, free chlorine and extraneously introduced CCl CClF in the proportion of 1.13 .mols' of HF, 0.50 mol CCI CCl f; 0.5 mol of C1 and 0.2 mol of CCl CClF and the mix: ture introduced at the rate corresponding with 0.5 molof Q CCl CCI per hour into the inlet end of the nickel tube Contact.

and passed through the bed of ZIP; catalyst. time was about 6 seconds. Temperature of thecatalyst bed was maintained throughout the run close to and'at a maximum of about 347 C. Gaseous products were handled as in Example 1, and afterabout 4 hours operation was discontinued. Condensates from the initial gas cooler, the water scrubber and the lower temperature con; denser were combined and distilled. Of productsformed, there were recovered 22 mol percent CCl CCl F,'l6 mol percent CC1 CClF and 62 mol percent of CCIZFCCIQ' containing about 2% by weight of CCl CF About 415 grams of CCI FCCIF were recovered per hour per liter of catalyst. The 16 mol percent'of CCl CClF value represents the difierence between the total amount of CCl CClF recovered and-the amount of CCl CClF ex traneously introduced into the reactor during operation: Hence, in over-all effect, substantially none of the ex traneously introduced CCl CClF underwent reaction; and the indicated CCl CClF value represents the net of CCl CClF formed duringthe, operation. Utilization of row materials was 83% of the HF, 78% of the C Cl and 78% of the chlorine.

Example 6. -The same catalyst and apparatus as in Example 4 were employed. Liquid CCl =CC1 was vaporized and mixed with gaseous anhydrous HF, free chlorine and extraneously introduced CCl CClF in the proportion of 1.19 molsof HF, 05 mol CC1 CCl 0.5 mol of C1 and 0.41 mol of CCl CClF- and the mixture introduced at the rate corresponding With 0.5 mol of CCl =CCl per hour into the reactor and passed through the bed of ZIP. catalyst. Contact time was about 5%- seconds. Temperature of the catalyst bed was maintained throughout the run close to and ata maximum of about 326 C. Gasous products were handled as in Example 1, and after about 3 hours, operation was discontinued. Condensates were combined and distilled; Of products formed, there were recovered33 mol percent CCI CCI F, 7 mol percent CCl CClF and 60 mol percent of CCI FCCIF containing about 0.7% by weight of CCl CF r About 345 grams of CCl FCClF were recovered per hour perliter of catalyst. The 7 mol percent of CCl CClF value represents the difference between the total amount of CCl CClF recovered and the amount of CCl CClF extraneously introduced into the reactor during operation. Hence, in over-all effect, substantially none of the extraneously introduced CCl FCClF under- Went reaction, and the indicated CCl CClF value represents the net of CCl CClF formed during the operation. Utilization of raw material was 67% of the HF, 68% of the C Cl and 68% of the chlorine.

Example 7.-ln this run, the same catalyst and apparatus as in Example 4 were employed. Liquid CCl =CCl was vaporized and mixed with gaseous anhydrous HF, free chlorine and extraneously introduced CCl CClF in the proportion of 1.2 mols of HP, 0.5 mol CCl =CCl 0.5 mol of C1 0.41 mol of CCl CClF and the mixture introduced at the rate corresponding with 0.5 mol of CCl =CCl per hour into reactor and passed through the bed of ZrF catalyst. Contact time was about 5 /2 seconds. Temperature of the catalyst bed was maintained throughout the run close to and at a maximum of about 340 C. Gaseous products of the reaction were handled as in Example 1, and after about 3 hours, operation was discontinued. Condensates were combined and distilled. Of products formed, there were recovered 27 mol percent CCl -CCl F, and 73 mol percent of CCl FCClF containing about 1.6% by weight of CCl CF About 485 grams of CCI FCCIF were recovered per hour per liter of catalyst. Utilization of raw materials was 81% of the HF, 73% of the C CI and 73% of the chlorine. The total quantity of CCl CClF recovered was less than the quantity of extraneous CCl CClP introduced during the operation by an amount which showed that about 3 wt. percent of the extraneously introduced CCl CClF reacted with HP to form CCl FCClF The fact that total CCl CClF recovered was less than the amount of CCI CCIF extraneously introduced demonstrates that the CCl CClF by-product normally formed during the reaction and also part of the extraneously introduced CCl CClF were converted to sought-for CCI FCCIF this result being accompanied by continuance of the remarkably low unwanted CCl CF isomer formation.

Example 8.150 cc. .of about 4-14 mesh zirconium fluoride catalyst, prepared by procedure substantially the same as illustrated in Example A above and having crystallite size less than about 150 A., were charged into a nickel reactor tube provided wtih external electrical heating and inlet and outlet gas connections substantially as in the previous examples. Liquid CCl =CCl was vaporized and passed thru a pretreater tube packed with 150 cc. of about 14 mesh Columbia 6G activated carbon maintained by external heating at about 294 C. The gaseous CCl :CCl exiting the pretreater, without substantial cooling, was mixed with unheated gaseous anhydrous HF, chlorine and extraneously int oduced CCl CClF in the proportion of 1.17 mols of HF, 0.54 mol CCl =CCl 0.55 mol of C1 and 0.44 mol of CCl CClF and the mixture introduced at the rate corresponding with 0.54.mo1 of CCl =CCl per hour into the inlet end cf the reactor tube and passed through the bed of ZrR; catalyst. Contact time was about 6 seconds. Temperature of the catalyst bed was maintained throughout the run close toand at a maximum of about'250 C. Gaseous productsof the reaction were handled as in the previous examples, and after about 2 and one half hours, operation was discontinued. Condensates were combined and distilled. There were recovered 0.22 mol per hour or" CCl PCClF containing about 2.6% by weight of CCI CF i. e. about 268 grams of CCl FCClF were recovered per hour per liter of catalyst. Utilization of raw materials was 63% of the HF, 37% of the C Cl and 30% of chlorine. The total quantity of CCl CClF recovered was less than the quantity of extraneous CCl CClF introduced during the operation by an amount which showed that about 13 wt. percent of the extraneously introduced CCl CClF reacted with HF to form Recovery of less amount of CCl CClF than extraneously introduced shows that the CCl CClF by-product normally formed during the reaction and also part of the extraneously introduced CCl CClF were converted to sought-for CCl FCClF this result being accompanied by desirable maintenance of low unwanted CCl CF isomer formation.

Example 9.- cc. of about 4-14 mesh zirconium fluoride catalyst, prepared by procedure substantially the same as illustrated in Example A above and having crystallite size less than about 150 A., were charged into a nickel reactor tube provided with external electrical heating and inlet and outlet gas connections substantially as in the previous examples. However, the ZrF catalyst of this example, just subsequent to manufacture of HF gassing of ZrCl and prior to any use, was treated with commercial oxygen for about 30 minutes at temperature of about 460 C. Liquid CCl =CCl was vaporized and passed thru a pretreater tube packed with 150 cc. of about 4 mesh Columbia 6G activated carbon maintained by external heating at about 263 C. The gaseous CCl =CCl exiting the pretreater, without substantial cooling, was mixed with unheated gaseous anhydrous HF, free chlorine, and extraneously introduced CCl CClF in the proportion of 1.25 mols of HF, 0.50 mol 0.46 mol of C1 and 0.41 mol of CCl CClF and the mixture introduced at the rate corresponding with 0.50 mol of CCl =CCl per'hour into the inlet end of the reactor tube and passed through the bed of ZrF; catalyst. Contact time was about'6 seconds. Temperature of the catalyst bed was maintained throughout the run close to and at a maximum of about 280 C. Gaseous products of the reaction werehandled as in the previous examples, and after about 3 hours, operation was discontinued. Condensates were combined and distilled. There were recovered 0.25 mol per hour of Ccl FCClF containing about 0.7% by weight of'CCl CF i. e. about 312 grams of CCl FCClF were recovered per hour per liter of catalyst. Utilization of raw materials was 63% of the HF, 63% of'the C Cl and 68% of chlorine. The total quantity of CCl CClF recovered was about the same as the quantity of extraneous CCl CClF introduced during the operation.

I claim: a

1. The process for fluorinating CCIFCCI to form CCl FCClF whichprocess comprises introducing a gas phase mixture comprising-CCl cCl substantially anhydrous HF and free chlorine into a reaction zone containing substantially anhydrous zirconium fluoride catalyst having crystallite size not substantially greater than 400 Angstrom units radius and having been derived by reaction -of substantially anhydrous ZrCL; and substantially anhydrous HF, the amount of HF and free chlorine of the said gas phase mixture being sufficient to ultimately form a chlorofluorocarbon reaction product containing a substantial quantity of CCl FCClF heating said mixture in said zone at temperature in the approximate range of 225400 C. for a:time sufiicient to cause fluorinating reaction of a substantial amount of said CCl =CCl and effect formation of gaseous saturated chlorofluorocarbon reaction product containing no substantial amount of tetra-fluorinated chlorofluorocarbons and comprising a substantial quantity of CCl FCClF and below about 10% by weight of CCl CF based on the quantity of present, and discharging said gaseous chlorofluorocarbon reaction product from said zone.

2. The process for fluorinating CCl =CCl to form CCl FCClF which process comprises introducing a gas phase mixture comprising CCl =CCl substantially anhydrous HF and free chlorine intoaf reaction zone containing substantially anhydrous zirconium fluoride catataining a substantial quantity of CCl FCC1F heating said mixture in said zone at temperature in the approximate range of 240-375 C. for a time suflicient to cause fluorinating reaction of a substantial amount of said CCl =CCl and effect formation of gaseous saturated chlorofiuorocarbon reaction product containing no substantial amount of tetra-fluorinated chlorofiuorocarbons and comprising a substantial quantity of CCl FCClF and not more than about by weight of CCI3CF based on the quantity of Ccl FCClF present, and discharging said gaseous chlorofluorocarbon reaction products from said zone.

3.. The process of claim 2 inwhich there is recovered, from the reaction products discharged from said zone, CCl FCClF containing not more than about 5% by Weight of CCl CF 4. The proces forv fluorinating CCl =CCl to form CCI FCCIF which process comprises introducing a gas phase mixture comprising CClF-CClsubstantially anhydrous HF and free chlorine into a reaction zone containing substantially anhydrous zirconium fluoride catalyst having crystallite size not substantially greater than 400 Angstrom units radius and having been derived by reaction of substantially anhydrous ZrC1 and substanchlorofiuorocarbons and comprising a substantial quantity of CCl FCClF- and below about by weight of CC1 CF based on the quantity of CCI FCCIF present, and discharging said gaseous chlorofluorocarbonjreaction product from said zone, I

5. The process of claim 4 in'which extraneously introduced C cl F is present in amount in the approximate range of 0.l-1.0 mol proportions based on the amount of CCl =CCl fed.

6. The process for fluorinating'CCl CChtoform CCl FCClF which process comprises introducing a gas- 3 phase mixture comprising CCl =CCl substantially anhydrous HF and free chlorine into a reaction zone containing substantially anhydrous zirconium fluoride catalysthaving crystallite size not substantially greater than 400 Angstrom units radius and having been derived by reaction of substantially anhydrous ZrCl and substantially anhydrous HF, the amount of HF and free chlorine of said gas-phase mixture being suflicient to ultimately form a cblorofiuorocarbon reaction product containing a substantial quantity of CCl FCClF heating said mixture in said zonein the presence of extraneously introduced C Cl F in amount in the approximate range of 0.1-1.0

mol proportions based on the amount of.CCl =CCl fedat temperature in the approximate range of 240 375 C. for a time sufficient to cause fluorinating reaction of a substantial amount of said CCl CCl and effeet formation of gaseous saturated chlorofluorocarbon reaction product containing no substantial amount of tetra-fiuorinated chlorofiuorocarbons and comprising a substantial quantity of CCl FCClF and below' about 5% by weight of CCl CF -based on the quantity of CCl =CCl through a bed of activated carbon maintained at temperature in the range of about 250-400 C., thereafter introducing a gas-phase mixture comprising said carbon treated CClFCCl substantially anhydrous HF and free chlorine into a reaction zone containing substantially anhydrous zirconium fluoride catalyst having crystallite size not substantially greater than 400 Angstrom units radius and having been derived by reaction of substantially anhydrous ZrCl and substantially anhydrous HF, the amount of HF and free chlorine of said gas-phase mixture being sufiicient to ultimately form a chlorofluorocarbon reaction product containinga substantial quantityof CCl FCClF heating said mixture in said'zonein the presence of extraneously introduced C Cl F in amountin the approximaterange of 0.1-1.0 mol'proportions based on the amount of CCI CCI fed into said zone-at temperature in'the approximate range of 240300 C. for a time suificient to cause fluorinating reaction of a substantial amount ofv said CCIFCCI and effect formation of gaseous saturated chlorofiuorocarbon reaction product, containing no substantial amount of tetra-fluorinated chlorofiuorocarbons and comprising a substantial quantity of CCl FCClF and below about 5% byweight of CCl CF based on the quantity of cCl FCClF- present, discharging from said zone said gaseous chlorofluorocarbon reaction product, and recovering therefrom CCl- FCClF containing below about 5% by of CCI3CF3. i

References Cited in the file of this patent UNITED STATES PATENTS 

1. THE PROCESS FOR FLUORINATING CCL2=CCL2 TO FORM CCL2FCCLF2 WHICH PROCESS COMPRISES INTRODUCING A GAS PHASE MIXTURE COMPRISING CCL2=CCL2, SUBSTANTIALLY ANHYDROUS HF AND FREE CHLORINE INTO A REACTION ZONE CONTAINING SUBSTANTIALLY ANHYDROUS ZIRCONIUM FLUORIDE CATALYST HAVING CRYSTALLINE SIZE NOT SUBSTANTIALLY GREATER THAN 400 ANGSTROM UNITS RADIUS AND HAVING BEEN DERIVED BY REACTION OF SUBSTANTIALLY ANHYDROUS ZRCL4 AND SUBSTANTIALLY ANHYDROUS HF, THE AMOUNT OF HF AND FREE CHLORINE OF THE SAID GAS PHASE MIXTURE BEING SUFFICIENT TO ULTIMATELY FROM A CHLOROFLUOROCARBON REACTION PRODUCT CONTAINING A SUBSTANTIAL QUANTITY OF CCL2FCCIF2, HEATING SAID MIXTURE IN SAID ZONE AT TEMPERATURE IN THE APPROXIMATE RANGE OF 225-400*C. FOR A TIME SUFFICIENT TO CAUSE FLUROINATING REACTION OF A SUBSTANTIAL AMOUNT OF SAID CCL2=CCL2 AND EFFECT FORMATION OF GASEOUS SATURATED CHLOROFLUOROCARBON REACTION PRODUCT CONTAINING NO SUBSTANTIAL AMOUNT OF TETRA-FLUORINATED CHLOROFLUOROCARBONS AND COMPRISING A SUBSTANTIAL QUANTITYS OF CCL2FCCLF2 AND BELOW ABOUT 10% BY WEIGHT OF CCL3CF3 BASED ON THE QUANTITY OF 